Lift cell

ABSTRACT

A lift cell comprising an airfoil section or sections containing a plurality of airfoils enclosed within an enclosure and a device for forcibly moving air through the airfoil section or sections. The airfoils are shaped and arranged so that airflow past each airfoil creates a pressure differential acting on the airfoil to produce lift, the combined lift on each airfoil in the enclosure producing lift on the lift cell.

States Patent 11 1 I Sakai, .111". 1 1 Nov. 12, 11974 1 LIFT CELL 3,276,723 10/1966 Miller et 111. 244/23 c [76] e to J s ph A. Sa a J 7626 3,505,819 4/1970 Wilde 60/226 Barnsbury Dr., Union Lake, Mich. FOREIGN PATENTS OR APPLICATIONS 43085 1,072,615 9/1954 France 1. 244/23 R [22] Filed: .1ian.4, 1973 P E T M Bl rimary xammerrygve 11x [21] Appl. No.: 320,886 Assistant Examiner-Jesus D. Sotelo Attorney, Agent, or FirmHarncss, Dickey & Pierce [52] US. Cl. 244/13, 244/15 [51} Int. Cl. B64c 15/00 [57] ABSTRACT [58] g g s ?g 2 5 A lift cell comprising an airfoil section or sections CC 42 3 66/222 containing a plurality of airfoils enclosed within an enclosure and a device for forcibly moving air through [56] R f Ct d the airfoil section or sections. The airfoils are shaped e erences I e and arranged .so that airflow past each airfoil creates a UNITED STATES PATENTS pressure differential acting on the airfoil to produce 1,373,409 4/1921 Caspar 244/12 R lift, the combined lift on each airfoil in the enclosure 1,389,797 9/1921 Thompson i 1 244/23 R producing lift on the lift cell. 1,801,356 4 1931 Love1and..; 244/15 1,843,926 2 1932 MacCaskie 244 12 13 Z Clan/118,6 Drawing gu s /4 Far fhzz/Jm flzh/fl/ filmy/12221071 \flWlrf/zmf f2 22%?7/ [0 f/zfi'a/r If) a 257 1/7/12! I 11 a a hi fi 242%: a W /fl/d: :2 :it/d: 5 27/6: 5%: 74 4/ :3 41/5 4 E E E E a 452,352; 2. 3 Li: gfii g E fAl/E E E 52/ 5 %z%z a 2%; :W/1: 2/41: 353ml: z z 5 2; 2

PATENTEBnuv 12 1974 3,847,368

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FIG. 2 is a view similar to FIG. 1 illustrating a modified form of lift cell according to the present invention.

FIG. 3 is a vertical, sectional view taken'along line The present invention relates generally to powered 3-3 in FIG. land having a portion broken away.

namic lift. According to this theory, lift is generated by,

propelling oneor more airfoils through the air at a ve locity sufficient to impart lift to the airfoil,- the lift force being generally perpendicular to the direction of air-.

flow relative to the airfoil. This-theory is embodied in many present-day aircraft and as a result such aircraft require a relatively longrunway for takeoff and landing. Another theory, which may be called the deflection theory, involves'the deflection of air in a downwardly direction to develop an upward reaction, or lift. Structures which operate on the deflection theory have insufficient airfoil surfaces for developing aerodynamic lift, and in general, operate rather inefficiently since a large amount of power is required to create airflow.

In contrast to prior arrangements, the lift cell of the present invention develops high-velocity airflow through itself and passes the same over a series of airfoils mounted within the liftcell. In this way, aerodynamic lift is efficiently developedcontinuously both, prior to, during, and after becoming airborne, and lift FIG. 4 is an enlarged, fragmentary view taken in the direction of arrow 4 in FIG. 1.

FIG. 5 is a planview illustrating one usage of the lift cell of the present invention. FIG. 6 is a side elevational view illustrating another usage of the lift cell of the present, invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Turning first to FIGS. 1, 3 and 4, a'lift cell 10, according to the present invention, comprises a forward ducted fan section 12, an intermediate airfoil compart- 22b continuing rearwardlyof segment 22a. The shape of the forward portion of enclosure 22 is the same as the shape of the forward portion of the upper surface of an airfoil. As will be discussed later, this provides forward linear motion to the lift cell during operation. Motor 20 is centrally supported within enclosure 22 at the rear portion of segment 22b by means of a plurality of engine mounts 24. A propeller 26 is affixed to the forwardly extending shaft of motor 20 and is longitudinally positioned at approximatelythe juncture of segments 22a and 22b. The diameter of propeller 26 is just is not lost due to insufficient air speed as may occur in I a stall of conventional aircraft. Furthermore, with the lift cell of the present invention, a takeoff run is unnecessary, and takeoff and landing can be effected within relatively short ground distances. Additionally, an extremely stable aerial platform is available since the center oflift is distributed horizontally throughout the longitudinal enclosure of the lift cell.

slightly less thanthe inside diameter of surrounding portion of enclosure 22. When motor 20 is operated, propeller 26 draws air into lift cell 10via the open end of enclosure 22 and moves the air through airfoil sec tion 14. Since a ducted fan requires a high fan, speed in Further advantages of the present invention are the high degree of compactness of the lift cell which may be constructed to have no protruding elements and.

BRIEF DESCRIPTION OF THE DRAWINGS The drawings illustrate a preferred embodiment of the invention in accordance with the best mode presently contemplated for carrying out the invention.

FIG. I is a .vertical, longitudinal, sectional view through a lift cell according to the present invention.

comparison to the speed availablewi'th reciprocal engiries, it is preferable to use an engine having a high shaft speed, for example, the type used inturboprop aircraft. Alternatively, it is contemplated that other power plants (e.g., jet engines) may be used.

Airfoil section 14 is of a generally rectangular configuration comprising an enclosure 28 of rectangular transverse cross section which continues rearwardly from enclosure 22 for the fulllength of section 14. The rear portion of enclosure 22 may be blended into the forward portion of enclosure 28 in four places as indicated at 29 in FIG. 3. Section 14 further comprises a plurality of individual airfoils designated by the base numeral 30. Airfoils 30 are arranged in an array within the confines of enclosure 28, and the base numeral 30 of each airfoil is literally and numerically suffixed according to its orientation within enclosure 28. In the preferred-embodiment of FIG. 1, airfoils 30 are arranged in a series of horizontal and vertical rows. Accordingly, the literal suffix of each base numeral 30 identifies the vertical row in which the airfoil so designated is located; and the numerical suffix which follows the literal suffix identifies the horizontal longitudinal row in which the airfoil so designated is located. With this designation, the airfoils 30 in the forwardmost versuffix 1. Each vertical row comprises a plurality of six airfoils which are equally vertically spaced, and each longitudinal row a'plurality of eight airfoils. Thus, the lowermost and forwardmost airfoil 30 is identified by the numeral 30al, while the rearmost and uppermost airfoil 30 is identified by the numeral 30h6. The vertical rows are uniformly longitudinally spaced, but the individual airfoils'in immediately adjacent vertical rows are vertically offset relative to the corresponding airfoils in the adjacent rows. Thus, itwill be observed in FIG. 1 that airfoils 30a, 30b and 300 of eachlongitudinal row are disposed at increasingly higher vertical elevations and that this pattern is repeated in succeeding vertical rows, i.e., 30d, 302,30f, 30g, 30h.- As shown in FIGS. 3 and 4, each airfoil 30 extends laterally straight across enclosure 28. The end tips of each airfoil 30 are pivotally mounted on the side wall of enclosure 28 in suitable bearing joints. For example, each airfoil 30 may be pivoted for movement about a lateral axis extending along the trailing edge of the airfoil. Each airfoil 30, moreover, is shaped and constructed in accordance with known airfoil design so that air flowing longitudinally past the airfoil creates a pressure differential thereacross producing aerodynamic lift. De-

sir'ably, the angle of attack of each airfoil is identical, as is the angle of incidence of each airfoil. However, with regard to the angle of incidence, it may be beneficial to have a slightly higher angle of incidence (perhaps a degree or two) for the more rearward rows of airfoils to adjust for loss of airflow effectiveness from forward to rear rows of airfoils. All airfoils are operatively coupled by means of suitable control mechanism (details of which are omitted from the drawing for sake of clarity) for actuation in unison to adjust the angle of attack. Control of the angle of attack may be effected by means of control arms attached to the midpoints of each airfoil. in each vertical row. These are able to swivel and all'are interconnected to a control arm in the cockpit area, In accordance with known airfoil theory, the lift developed on each airfoil is a function of the angle of attackfSeparatin g successive vertical rows of airfoils are diverters designated 32a through 321'. Diverters 32 are parallel to airfoils 30, but lie in longitudinal planes to thereby enhance the longitudinal flow of air through section 14. Suitable clearance is provided between airfoils and diverters 32 over the range of adjustment positions of the airfoils.

Rear compartment engine and venturi section 16 comprises an enclosure of circular cross section 34 whichforms a continuatio of enclosure 28. An additional continuation 36 is centrally mounted within enclosure 34 at the forward portion thereof by a plurality of engine mounts 38. The shaft of engine 36 extends rearwardly and a propeller 40 is affixed thereto. The

interior of enclosure 34 is in the shape of a venturi 42 and propeller 40 is longitudinally aligned approximately with the narrowest diameter of venturi 42. When engine 36 is operated, propeller 40 pulls air through airfoil section 14, thereby aiding ducted fan 18. The air passing through the lift cell is discharged via the rear of section 16 for effecting pitch and roll control of the lift cell. Suitable controls (which are omitted from the drawings for sake of clarity) are included to effect the desired actuation of stabilizers 44 and 46. A pair of landing gears 48 are mounted on the underside of lift cell 10. i v

Considering now the operation of lift cell [0, engines 20 and 36 are operated to draw air into lift cell 10, flow .the air through section 14 and discharge the air from the lift cell. The provision of ducted fan 18 is particularly advantageous in that a substantially higher, on the order of about 40 percent more, thrust can be obtained from fan 18 than'from a propeller by itself. Hence, utili zation of ducted fan 18 provides a large volume of sufficiently high velocity airflow into section 14 which is necessary to develop lift onairfoils 30. Furthermore, the effective intake and discharge areas of the ducted fan are much greater thantheir geometrical areas, the effectiveness of the geometric area of the ducted fan propeller being much greater than that of the same pr'opeller byitself for the same engine power. Accordingly, the ducted fan also contributes to the compactness of the lift cell. Moreover, the ducted fan is inherently quiet due to the absence of propeller'tips flailing in the air. Section 16 aids ducted fan 18 in moving air through section 14, and the use of the venturi construction of section 16 affords improved air moving efficiency, and aids fan 18 in generating adequate velocity airflow through airfoil'section 14. The use of a ducted fan, as illustrated, provides an important operating benefit. The forward portion 22a of the ducted fan is longitudinally contoured to the shape of the forward portion of an airfoil section. The large frontal area of this forward duct portion permits a net forward force to be developed on the lift cell when operated,- the force being developed by the aerodynamic contour of portion 22a. As a result, lift cell 10 operates to provide a large vertical lift and also forwardhorizontal motion. The size of the frontal duct area can be reduced with the use of high power engines (for example, a jet engine) to allow larger horizontal forward speeds.

Regardless of the specific air moving means employed, the novel structure and concept embraced by a further aspect of the present invention relate to the arrangement and operation of section 14. By intaking air and moving it through airfoil section 14, lift cell 10 provides efficient lift which permits the use of relatively short ground distances for takeoff and landing. The structure of section 14 is important in developing this efficient lift. Airflow over and under each individual airfoil 30 creates a pressure differential across the airfoil tending to produce lift. The total lift on lift cell 10 is equal to the sum of the lifts on each of the individual airfoils. After the airflow passes over the airfoils of one vertical row, any turbulence is reduced by diverters 32, tending to enhance the longitudinal flow of air onto the airfoils of the next succeeding vertical row. In this way, it is intended to make the lift on each airfoil generally uniform so that imbalances in lift force on individual airfoils are reduced or eliminated. The construction of diverters 32 is such that minimum restriction on the airflow therethrough occurs. Accordingly, such diverters are desirably constructed of durable, but very thin material. The basic purpose of diverters 32 is to smooth out, and not to restrict, the airflow from each forward vertical row of airfoils and to direct this airflow hori zontally onto the succeeding vertical row of airfoils. It

is contemplated that refrigeration coils could be incorporated with diverters 32 to cool hot air and thereby promote lift efficiency. It will also be observed that the vertically staggered, or offset, arrangement of the airfoils of each successive vertical row of airfoils reduces the effect of turbulence at the trailing edge of the airfoils of the immediately preceding vertical row. By enclosing airfoils 30 within enclosure 28, the total airflow drawn into lift cell is thereby confined so as to be effective on each and every one of the airfoils over the full extent thereof. Moreover, by terminating the airfoils at the sides of enclosure 28, vortex drag on the tips of the airfoils is reduced, thereby providing more efficient lift. Desirably, the structure of the various enclosures of each section are constructed within an airtight, relatively light structure of suitable aircraft-type metal, such as aluminum, etc. It will be noted that the enclosures surrounding the three sections, 12,114 and 16, eliminate protruding elements, thereby enhancing safety to personnel and also compactness. Furthermore, the interior elements arev protected. It is contemplated that heating coils could be incorporated within the enclosure to eliminate any icing which may occur. The use of the rectangular structure for section 14 allows the use of standard size, maximum area airfoils and each airfoil can be made identical. While the use of a cylindrical or other structure for airfoil section 14 is within the scope of the present invention, such a structure would require variously sized airfoils and would restrict the net airfoil area, thereby reducing the lift capability of the unit. The airfoils are arranged so that they are allowed to travel from a negative angle of attack to a positive angle of attack. The maximum positive angle of attack setting is that angle allowable with given gross weight and engine horsepower to produce optimum lift. The negative angle of attack should be used for ground use only. The angle of attack is controlled by the previously mentioned control arrangement. However, in some instances where optimum lift only is desired, it would be possible to eliminate this control arrangement by fixedly positioning airfoils at the best angle of attack to develop maximum lift. If desired, the lift cell can be designed to incorporate swept-back airfoils.

The operation of lift cell 10 for takeoff and landing is now described. Engines 20 and 36 are operated to provide maximum power and hence draw maximum air into and through airfoil section 114. The airfoils are set to the angle of attack for developing maximum lift and the directional control, i.e., stabilizers 44 and 46, is maintained. Preferably, lift-off is made into the wind for better control. The lift cell will move forward and quickly rise vertically. The high degree of lift imparted by the present invention enables takeoff within a rela-' tively short ground space and it is contemplated the takeoff can be reduced to become even vertical under certain circumstances.

-While the primary purpose of the propellers 26 and 40 is to move air through the lift cell 114, the power units impart a certain amount of forward velocity to the lift cell (as discussed earlier) so that it is capable of travel, but at relatively slower speeds. However, one of the more important advantages of the arrangement is that a highly efficient lift is developed and the unit is capable of lifting relatively great masses in relation to its size and shape. Once unit It) is in flight, control is effected via the setting of airfoils 14 and stabilizers 44 and 46.

At landing, the engine power is throttled and the descent is controlled primarily by the angle of attack at which the airfoils 14 are set. A further advantage of the present invention is that lift cell 10 can maintain limited flight capability with loss of one of the two engines. This means that, in the event of power failure, lift cell 110 can be brought to a relatively safe touchdown. When there is total power failure, a nose-down attitude is necessary to develop sufficient airflow through the lift cell, but even in such an event, it isbclieved possible to manipulate the controls so as to achieve a relatively safe touchdown.

In constructing a lift cell according to the present invention, as exemplified by FIG. ll, the size of the unit depends upona combination of three factors to produce the desired lift. These are the airfoil aspect ratio, the propeller size, and the engine horsepower. Where the arrangement provides extremely high velocity airflow, for example, with a jet engine power unit, a more efficient lift cell of higher lift capacity and smaller dimensions can result. The use of a jet engine also permits the use of several additional high aspect ratio airfoils. Furthermore, it is desirable to balance the lift cell to a centrally located center of cavity. It is also contemplated that various airfoil and engine compartment sections may be constructed in modular form and interconnected as desired to provide various degrees of lift capability. It is also desirable to fit thin wire screens over the open ends of the lift cell to protect the interior thereof from foreign matter. The ducted fan keeps the operating noise level of the lift cell relatively low, thereby providing comparatively quiet performance for an aerial vehicle. It should also be mentioned that each of the ,diverters 32 could be combined with its corresponding vertical row of airfoils so that the length of section 14 can be reduced. This would permit more airfoils to be incorporated into a given length of airfoil section.

FIG. 2 illustrates a modified form of the invention I which differs from FIG. l in the following respects. A

venturi 43 is provided around the interior of the rear portion of ducted fan 18. The diameter of propeller 26 is correspondingly reduced to fit within venturi 43. Venturi 42, engine 36, engine mounts 38 and propeller 40 are eliminated. The inventive concepts discussed above for FIG. ll apply to FIG. 2.. Accordingly, it will be appreciated that the invention contemplates a variety of forms, thereby demonstrating the versatility of the invention.

FIG. 5 illustrates one possible utilization of lift cells lit) in an aircraft. A pair of lift cells 10 are attached to the sides of a fuselage 50. Fuselage 50 can contain passengers,'cargo, etc., and controls for actuating and operating the lift cells 10.

FIG. 6 illustrates a further possible application of lift cell 10. Here, a cockpit 52 is mounted directly on top of lift cell 10. In this instance, controls of the lift cell may be actuated from cockpit 52.

It is to be understood that the foregoing description is that of a preferred embodiment of the invention. Various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims.

What is claimed is:

1. In a lift cell having a horizontal longitudinal axis, the combination comprising a straight longitudinally extending enclosure means open at both longitudinal ends, an airfoil section comprising a plurality c'if airfoils distributed in an array within said enclosure means,

each airfoil being disposed in the path of airflow through said enclosure means and being shaped such that longitudinal airflow past the airfoil creates a pressure differential acting on the airfoil to produce lift, and a ducted fan section at the forward end of said enclosure means for drawing air into said enclosure means and forcing the same through said enclosure means and across the airfoils of said airfoil section to thereby impart lift to each airfoil and hence to the lift cell, said ducted fan section including additional enclosure means continuing longitudinally forwardly from the forward end of said first-mentioned enclosure means, said additional enclosure means having a straight cylindrical section extending forwardly from the forward end of said first-mentioned enclosure means and a flared section flaring radially outwardly in the forward direction from the forward end of said straight cylindrical section, said flared section being shaped to form a contoured aerodynamic surface via which a longitudinally forward thrust is imparted to the lift cell when the ducted fan section is operated to draw air into and through said two enclosure means.

2. The combination of claim 1 wherein said airfoils are arranged in successive vertical rows longitudinally along said enclosure means and further including diverting means disposed between adjacent rows of airfoils. 

1. In a lift cell having a horizontal longitudinal axis, the combination comprising a straight longitudinally extending enclosure means open at both longitudinal ends, an airfoil section comprising a plurality of airfoils distributed in an array within said enclosure means, each airfoil being disposed in the path of airflow through said enclosure means and being shaped such that longitudinal airflow past the airfoil creates a pressure differential acting on the airfoil to produce lift, and a ducted fan section at the forward end of said enclosure means for drawing air into said enclosure means and forcing the same through said enclosure means and across the airfoils of said airfoil section to thereby impart lift to each airfoil and hence to the lift cell, said ducted fan section including additional enclosure means continuing longitudinally forwardly from the forward end of said first-mentioned enclosure means, said additional enclosure means having a straight cylindrical section extending forwardly from the forward end of said first-mentioned enclosure means and a flared section flaring radially outwardly in the forward direction from the forward end of said straight cylindrical section, said flared section being shaped to form a contoured aerodynamic surface via which a longitudinally forward thrust is imparted to the lift cell when the ducted fan section is operated to draw air into and through said two enclosure means.
 2. The combination of claim 1 wherein said airfoils are arranged in successive vertical rows longitudinally along said enclosure means and further including diverting means disposed between adjacent rows of airfoils. 